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Framing Bias and More Information

August 26, 2011 at 3:00 pm

Don Taylor

Brad Flansbaum writes about the difficulty of correctly interpreting survival odds for patients and physicians. His post is based on an interesting study about framing bias in medical decision making. He notes that physicians, in particular, may have trouble communicating small survival chances in meaningful language, and seem to systematically overstate the chances for success as compared to patients. In the paper he is citing, two-thirds of physicians attached the label “clearly better” to a reduction in relative risk of death of one-third, and absolute mortality risk reduction of 2%. Interestingly, around half of the patients in this study attached the label “clearly better” to this same risk reduction.

Brad is particularly worried about the ability of physicians to deliver information to patients in a meaningful format, which is one key component of good treatment decisions. How do we improve decision making?

I think that the best answer is more types of information to inform decisions. We need to add quality of life and cost to the mix to arrive at better decisions. Better communication about survival chances would be an improvement, but that is only part of the answer, and in and of itself won’t likely reduce costs as much as many seem to assume. Belief that better prognostication of death will lead to great cost reductions is likely the “fools gold” of health reform. We need to add information on the impact of a treatment on quality of life as well as explicitly discussing the costs of the therapy. More variables to consider, each with uncertainty, provide a more realistic setting in which to make treatment decisions. Only by learning to more directly encounter and talk about the trade-offs between survival, quality of life and cost can we hope to arrive at a reasonable answer to the bottom line questions: “is it worth it?” “should we do it?” My book has a fairly detailed discussion of these issues in chapters 3, 5 and 6.

I occasionally tell med students that medicine is the art of applying large scale population statistics to individual patients. Sometimes, it is pretty difficult to know what one should do. Still, we need to get past the idea of doing stuff just because we can. We need a better sense of value for the care that we offer.

I have some background in statistics and understand that the absolute mortality risk reduction of 2% is far more meaningful than the one-third reduction. The latter is a much more powerful statement, however, and I couldn’t say with any certainty that it wouldn’t influence my decision. Similarly, a 50% reduction in mortality from 2 in 10,000 (for treatment A) to 1 in 10,000 (for Treatment B) sounds so much more meaningful than it is. Saying that taking treatment B doubles my chances of dying would be an even more powerful, if equally meaningless statement.

@ George
I agree it is hard to understand and communicate. I think one of the hardest things for us culturally to get is that the probability of death in 100%. This means that all the things we do to forestall the inevitable eventually stop working. Doesn’t mean we should try, it just means we should expect to be looking for signals that doing more won’t work.

I agree that it’s not just a communication issue. Valuing life is and should always be a core principle of our society, but any principle can be pushed to extremes. Despite the potential for setting a record for sophistry, hysteria, and political cheap shots, a national discussion of what medical necessity means for publicly funded programs is badly overdue. What people do with their own money is their business, but elected officials have a duty to decide how small a chance of extending someone’s life and how short an extension tens if not hundreds of thousands of tax payers dollars should be spent per patient to pay for.. I

Once that decision is made, the question of whether something is medically necessary, whether it meets that criteria becomes a scientific question.

@George
we have to figure out how to make such a discussion an expectation and not such a hot button political topic. I think this is a case where the politicians are mostly responding to the incentives provided by the culture.